Holmes, Maple, and Kogoro are no ordinary elementary school students. They are associated with many police activities. Yup, the police has recruited them as secret investigators. Their analytical ability is out of normality.
If you notice their nicknames derives from famous detective characters:
Holmes –Sherlock Holmes (Sir Arthur Conan Doyle)
Maple –Miss Maple (Agatha Christie)
Kogoro –Kogoro Akechi (Edogawa Ranpo)
Inuki Eiji Sensei completed this manga in 9 volumes.